Valve for rock drills



patented et. 20,1931

PATENT OFFICE UNITED: STATES JOHN c'. cuE'rIs'or EAsroN, PENNSYLVANIA,ASSIGNOR T0 INGERSOLL-BAND COM- IPANY, or EsEY' CITY, NEW JERSEY, ACORPORATION or nEw JERSEY VALVE r03 noon DRILLS Application filedNovember 1, 1929. Serial No. 404,010.

This invention relates to rock drills, but more particularly to adistributing valve for rock drills of the fluid actuated type. V

The objects of the invention are to obtain a quick and positive actionof thevalve, to assure aheavy blow of the hammer piston against theworking implement, and to control the supply of pressure fluid to theends of the piston chamber in such manner that the hammer piston willstrike heavily against the working implement onits forward stroke andthat the hammer piston is actuated rearwardly without causing theobjectionable jar or shock which usually takes place in machines of thischaracter.

Other objects will be in part obvious and in part pointed outhereinafter.

In the accompanying drawings forming part of this specification and inwhich similar reference characters refer to similar parts, t

Figure 1 is a sectionalelevation of a rock drill equipped with a valveconstructed in accordance with the practice of the invention, the valvebeing shown in position to supply pressure fluid to the rearward end ofthe piston chamber, and a p 7 Figure 2 l .is a similar view showing thevalve in a position tosup'ply pressure fluid to the front'end of the:piston chamber.

Referring more particularly to the drawings, A designates generally arock drillcom= prising a cylinder B wherein is fo'rmed a piston chainberC to accommodate a'reciproca- I toryhammer piston D. In the wall of thecylinder B is a piston controlled exhaust port E to afford communicationbetween the piston chamber C and the atmosphere.

A suitable closure is provided for the front end of the piston chamberCin the form of a head F which may alsoactas a guide fora workingimplement Gr shown as extending with its rearward, end'into the pistonchamber to receivethe blows of the hammer piston A closure isprovidedfor the rearward end ofthe'pistoncham'ber in the form of a plate jHwhereonis seated at head block J which in turn serves as a seat for aback head K.

The cylinder B, the head F and the elements designated by H, J and Kform the casing parts of the rock drill and such parts may be held inassembled relationship in any Sllltflblfi and convenient manner, asforinstance, by .the usual side bolts (not shown). In accordance with thepractice of the in 'v'entionthe head block J is provided with a bore Lto receive a valve chest 0 having a bore to form a valve chamber P. TheValve chamber P comprises an enlarged portion Q and a reduced portion Rto accommodate a distributlng valve S having a hood or stem "T whichextends slidably into the reduced portion R to form a bearing portionfor the valve. -The valve S cess or cavity U to reduce its weight. Nearthe forward end of the valve is an integral *fla'nge V which lies in theenlarged portion Q and spaced slightly rearwardly of the flange V isanother flange WV which also lies "within the enlarged port-ion Q.

The pressure fluid intended to be distributed by the valve is introducedbetween the flanges V and W by a port or ports X in the,

valve chest 0 and the ports X communicate with asupply conduit Y throughan annular'passage Z in the head block J.

The pressure fluid utilized for impelling the piston D forwardly isadmitted into the rearward end of the piston chamber C through a rearinlet passage Z) in the plate H and coaxially with the valve S. Thepressure fluid utilized for driving the piston D the piston chamber by afront inlet passage 0 which extends through the cylinder B, the plate Hand the head block J and communicates with the rearward end of theenlarged may be provided with a re rearwardly is conveyed to the frontend of portion Q of the valve chamber through ports (Z in the valvechest 0.

In the flange V are a series of ports 6 through which the pressure fluidflows to the rear inlet passage 6 and the pressure fluid supplied to thefront inlet passage 0 flows through ports f in the flange WV. The portsare preferably of greater area than the ports f so that a greater amountof pressure fluid may be supplied to the rearward end of the pistonchamber within a given time than to the front end. This is desirable forthe reason that the forward stroke of the piston is the working stroke.

Convenient means are provided for actuating the valve S from onelimiting position to the other. To this end the flange-V is pro-' videdat its forward end with an annular nressure area against which thepressure fluid flowing through the ports 6 may act to throw the valverearwardly. Similarly a pressure area it is formed on the rearward endof the flange W so that pressure fluid flowing through the ports 7 willact thereagainst to throw the valve to its forward limiting position. 7

Additional means are, however, provided to assist the pressure fluidacting against the pressure areas 9 and h in throwing the valve.

The valve is accordingly provided with an actuating surface againstwhich compression from the rearward end of the piston chamber may act toassist the pressure fluid acting against the pressure area 9 to-throwthe valve rearwardly. At the rearward end of the flange V is an annularactuating surface [13 which is subjected to compression from the frontend of the piston chamber 0 to assist the pressure fluid acting againstthe actuating surface 71- in throwing the valve forwardly. Preferablythe rearward end of the reduced portion B of the valve chamber is 3vented to the atmosphere, as for instance, through the through a passage0 which leads valve chest 0 and the back head K. g

The operation of the device is as follows:

With the valve in the rearward position ilpressure fluid will flowlustrated in Figure 1, through the ports 6 into and through the frontend of the valve chamber P and thence through the rear inlet passage 6into the back end of the piston chamber to drive the piston D forwardly.the pressure fluid through the front end of the piston chamber, suchpressure fluid will act against the pressure area 9, as Well as theactuating surface 7', to hold the valve S rearwardly. At the same time,however, pressure fluid will flow through the ports and the flange W toact against the pressure area it of the flange V. But, owing to the factthat the entire forward surface of the valve is exposed to pressurefluid" and this area is considerably greater than the pressure area 7L,

During the passage of the valve will remain in its rearward position.

As the piston D continues forwardly the air in the front end of thepiston chamber 0 will be compressed thereby and such compression flowingthrough the inlet passage 0 will then act against the rearward actuatingsurface is, so that immediately after the piston D uncovers the exhaustport E and at which time there will be an abrupt drop of pressureacting, against the forward. end of the valve, the pressure fluid actingagainst the pressure area it and the compression acting against theactuating surface 7c will throw the valve forwardly; c

In the new position of the valve, pressure fluidwillflow from betweenthe flanges V and W through the ports f and through the enlargedportion-Q- cf the valve chamber into the ports (Z and thence through theinlet passage 0 into the front end of the piston cham ber to return thepiston to its initial posi tion. As'during the forward stroke, thepiston D will compress the air in the front end of the piston chamberand such compression will act against the actuating surface j to sistthe pressure fluid acting against the pressure area 9 to again throw thevalve rearwardly.

I claim:

1. In a fluid actuated rock drill, the com-- bination of'a' cylinderhaving a piston chamber and a pistonin the piston chamber, an exhaustport in the cylinder, a valve chest having a valve chambeninlet chambersleading from the endsof the valve chamber to the piston chamber, a valvein the valve chamber controlling the inlet passages and having a pair offlanges, a supply passage for supplying pressure tl'uid to the valvechamber between the flanges, pressure surfaces on the flanges, ports inthe flanges to supply pressure fluid'to the pressure surfaces forthrowingthe val-ve and for supplyingpressure fluid to the inletpassages, and an eXtension on one end of the valve forming a bearingportion for the valve.

' 2i Ina fluid actuatedrock drill, the combination of a cylind'erhavinga piston cham ber and a piston in the piston chamber, an

exhaust port'in the cylinder, a valve chest having a valve chamber,inlet passages lead ing from the valve chest to the piston chamber, 'avalve in the valve chamber having a pair of flanges, annular pressureareas on the flanges, ports in theflan'ges to supply pressure flu-id tothe pressure areas for throwing the valve to supply pressure fluid tothe inlet passages, an actuaing surface on one end of the valvesubjected to compression to assist in throwing the valve in one.direction, and an actuating surface on the other end of the valve ofsmaller area than the" first said actuating surface and subjected tocompression from the piston chamher to assist in throwing the valve inthe opposite direction.

3. In a fluid actuated rock drill, the combination of a cylinder havinga piston cham-. her and a piston in the piston chamber, an

7 exhaust port in the cylinder, a valve chest 4:. In a fluid actuatedrock drill, the'comto the piston chamber, a valve in the valve chambercontrolling the inlet passages, said valve having a central cylindricalbody with a pair of external flanges thereon, a supply passage forsupplying pressure fluid to the valve chamber between the flanges,pressure surfaces on the flanges, ports in the flanges to supplypressure fluid to the pressure surfaces for throwing the valve and forsupplying pressure fluid to the inlet passages, and an extension on oneend of the valve forming a bearing portion for the valve.

In testimony whereof I have signed this specification.

JOHN G. CURTIS.

bination of a cylinder having a piston oham her and a piston in thepiston chamber, an

exhaust port in the cylinder, a valve chest having a valve chamber,front and rear inlet passagesleading from the valve chamber to thepiston chamber, a valve in the valve chamber to control the inletpassages and having a pair of flanges, pressure areas on the flanges, aport in one flange to supply pressure fluid to one pressure area and tothe front inlet passage, and a port in the other flange of greater areato supply pressure fluid to the other pressure area and to the rearinlet passage.

5. In a fluid actuated rock drill, the combination of a cylinder havinga piston chamber and a'piston therein, an exhaust port for the pistonchamber controlled by the piston, a valve chest having a valve chambercomprising an enlarged and a small portion, rear and front inletpassages leading from the ends of the valve chamber to the pistonchamber, a valve in the valve chamber to control the inlet passages andhaving a stem operable in the reduced portion of the valve chamber, apair of flanges on the valve lying in the enlarged portion of the valvechamber, an-

nular pressure areas on the flanges against which pressure fluid acts tothrow the valve, an actuating surface on the front end of the valvesubjected to compression to assist in throwing the valve rearwardly, anopposed actuating surface on the valve of smaller area than the firstsaid actuating surface'and against which comgpression acts to assist inthrowing the valve forwardly, ports in one flange through which pressurefluid flows to the rearward actuating surface and to the front inletpassage, and ports in the other flange of greater area than the firstsaid ports to supply pressure fluid to the forward pressure area and tothe rear inlet passage.

6. In a fluid actuated rock drill, the combination of a cylinder havinga piston chamber, an exhaust port in the cylinder, a valve chest havinga valve chamber, inlet passages leading from the ends of the valvechamber

